Reflective lamps



Feb. 23, 1965 R. G. NORDQUIST 3,170,636

REFLECTIVE LAMPS Filed April 15, 1963 2 Sheets-Sheet 1 INVENT OR F I 6.3 ROBERT G. NORDQUIST BY 'gmzmuu, 7

ATTORNEYS Feb. 23, 1965 R. s. NORDQUIST REFLECTIVE LAMPS 2 Sheets-Sheet2 Filed April 15, 1963 FIG.5

INVENTOR ROBERT G. NORDQUIST BY KW VwAw ATTORNEYS United States Patent3,17tl,636 REFLECTEVE LAMPS Robert G. Nordquist, Springfield, Ulric,assignor to Grimes Manufacturing Company, Urhana, Ohio, a corporation ofOhio Filed Apr. 15, 1963, Ser. No. 272,967 11 Claims. (Cl. 240-413) Thisinvention relates to the art of reflective type lamps, and particularlyto improvements therein by which a greater amount, if not 100%, of thelight energy from the source is utilized.

In the following discussions, utilization of light rays or energyemanating from a light source is referred to without regard to any lossfrom the reflective surfaces or lens. In other words, it is assumed forpurposes of these discussions that the reflectors and lens reflect andtransmit received light at 100% efficiency. Of course, in practice, thisis not necessarily fully accurate, but the approach thereto issufficient to consider it here in this manner.

.In the past, lamps with reflectors of various configurations have beenemployed, but either the reflector or reflectors were of improperconfiguration or did not reflect a sufficient amount of light rays, orhad the wrong portion of the reflector blocked off by the bulb base,

- to give the maximum possibility of light utilization from anapproximate point source of light such as the filament ina light bulb.

It is the primary object of this invention to provide a lamp havingfirst and second dome means facing each other with the first dome meansbeing of ellipsoidal shape and the other of hemispherical shape andhaving a center coinciding with the first focal point of the ellipsoid,with a source of light being disposed at the coinciding points, and withthe hemispherical dome means having a light aperture at its vertex sothat all light rays pass through the light aperture either directly orby reflection from one or both of the dome means, there being a supportfor said light source extending through the hemispherical surface at anangle to the major'axis i ing surface which is blocked is that which isat the lower side of the focal point, as is the situation in thisinvention.

7 Another object of this'invention is to shape the ellipsoidalreflecting surface such that the further focal point thereof is betweenthe first focal point and a planeconvex lens which then collects thereflected light rays as they diverge from the second focal point andalso col lects the direct light rays received through the light apertureto provide from the lamp a controlled cone of light,

It is also an object of this invention to provide such a lamp as aboveindicated for a variety of purposes inf cluding, without limitationintended, aircraft lamps such as overhead passenger reading lamps andcargo flood lamps, marine lamps and bed lamps.

Further objects and advantages of this invention will "ice becomeapparent upon reading the appended claims and the following detaileddescription of several embodiments of the invention in conjunction withthe drawings, in which:

FIGURE 1 is an elevational view with the bulb socket rightward;

FIGURE 2 is an elevational view locking leftward at FIGURE 1;

FIGURE 3 is a cross sectional view taken along the lines 33 of FIGURE 2;

FIGURE 4 is a plan view of FIGURE 2 With the ellipsoidal reflecting cap,removed;

FIGURE 5 is a diagrammatric illustration of another embodiment; and

FIGURE 6 is another diagrammatic embodiment of the invention.

With regard to the embodiments shown in FIGURES 14, it may be notedthatthere is a first domemeans l0 and a second dome means 12. As isreadily apparent, these domes are inverted relative to each other sothat their interior surfaces face one another. Additionally,

their interior surfaces are reflective in nature, so that actually domeslit and 12 are reflectors which interiorly reflect rays of lightemanating from a source or filament 14 of a conventional bulb 16 whichhas a base 18, of the bayonet type for example. Filament 14 is supportedin the usual manner by electrically conducting wires 20 embedded in aglass bead 22 which upstands from base 18. I 1

Light bulb-16 is disposed in a conventional bayonet socket 24 so thatits center terminal is in firm contact with spring 26 which, in turn, isin electrical contact with a metallic element 28. This latter elementextends upwardly about insulator 30 to a screw-threaded terminal 32. Onthe other hand, the other terminal of light bulb 16 makes firm contactvia the outer periphery of base 18 with a metal socket element 34 whichextends outwardly past an insulator to a second screw-threaded terminal36. As is particularly apparent from FIGURES 3 and 4, socket 24 extendsthrough an aperture in the side of reflector l2, and the angle ofextensionttherethrough-is acute relative to the longitudinal axis 38 ofreflectors 10 and 12.

The two reflectors 1t) and 12 are releasably secured together byresilient detents or retaining springs 40, of

; which there may be three, for example, equally spaced about thecircumference of the domes.

at its uppermost end an enlarged diameter or rim 42 Reflector 12 haswhich receives the edge of reflector it To release reflector Iii fromdetents as and remove it from the rim 42 so that light bulb 15 may bereadily replaced for example, there is secured to the reflective cap Itas by rivet 44, a convenient upstanding finger-gripping ring 46, whichwhen pulled upwardly will separate the two reflectors.

Reflector lit is the vertex portion of an ellipsoidal surface cut on thefocal plane 48, which passes perpendicularly of the major axis 38through the closer focal point 50, i.e., the one that is more adjacentthe vertex than the second focal point 52. Because reflector it? isellipsoidal, all light rays emanating from the filament source 14 atfocal point 5@ and impinging on the reflector it) will be reflectedthereby back through the second focal point 52, as is evident by theillustrated light rays.

In order to prevent the loss of light rays which emanate ,from filament14 in a downward direction at an angle light aperture 54, reflector 12is made hemispheroidal so reflective material, except for alightaperture 74.

this embodiment the second focal point '76 is at a.sub-

that all light rays which impinge on its surface will be reflecteddirectly back through the upper focal point 559 and thence onto theellipsoidal reflecting surface by virtue of which they are reflected tothe outer focal point 52. The focal plane 43 of the ellipsoidalreflector is also the equator plane for the hemispherical reflector 12,

tax reflector 78. The hemispherical reflector Sil has in and the tworeflectors are centered so that focal point 58 is also .the center ofreflector 12.

- Light aperture 54, which in the embodiment being-described is acircular opening in .the hemispherical reflector l2 centered on majoraxis 38, has'secured'to its periphery in any convenient manner a lensholder 56, which holds not only a plane-convex lens 58,'but also a glassfilter lens 6%) which is for the purpose of breaking up lightstriationsin the rays receivedthereby. As is evident from FIGURE 3 the secondfocal point 52 is between the first focal pointStl and lens 58.

Therefore, lens 58 collects light rays which. are diverging from focalpoint 52 and converges them intoa controlled light cone '62 of or so, asdesired. The direct light rays front focalpointtill are also controlledbylens 58.

In the embodiment. of FIGURES 1-4, it will be noted from FEGURE 3' thatthe. second focal point 52 is on the major axis 38 at approximately thepoint where completion of the hemisphere of reflector 12 would intersectthat axis. Because focal pointsfitl and 52 can be so close together,i.e., because focal point 52 can be in that general area, the overallheight ofthe lamp can be made minimum because lens 58' can consequentlybe positioned close to the light aperture 54 in reflector i2. Carefulconstruction is necessary in making reflector ill ofijust therightellipsoidal configuration to place-the lowerfocal point 52 at thedesired position. which enables arelatively smalllamp to providea con- 7"trolled cone of light at a relatively high output, the feaj ture of thelight bulb base it; and socket 24- blockingrefiection only from arelatively small area of the hemispheroidal; reflector being. amain-contributor to the. high intensity of the attained output from thelamp.

Another embodiment ofthis invention-is illustrated diagrammatically inFIGURE 5. This is an embodiment which is itself a light bulb the glass.envelope of which This feature is that it a light aperture 84, which isnot coated with reflective 7 material as is the ellipsoidal reflectorand-the remainder is made available for use without any loss in thenumberof light rays.

Thus, there has been disclosed. several embodiments of this inventionwhich provide for the objects and ,ad-

vantages previously mentioned. Otherv objects, advantages, and even-rnodificationsf of this invention 'will occur to those of ordinaryskillin the art uponreading this disclosure,-but it is to be realized*thatjthis disclosure is intended to be exemplary and not limitative,the scope of the invention being defined bythe appended claims; What isclaimed is: g

1. 'A lamp comprising first dome means forming .an ellipsoidalinteriorly-re'flecting vertex surface having :a major axis containingfirst and secondfocal points respectively'at further distances from thesurface, the edge of said stirfacetermin'ating substantially in thefirst'focal 30;

point planewhich is perpendicular to said axis, second dome meansconnected to said first dome means: and forming a hemisphericalinteriorly-reflecting surface which faces said ellipsoidal surfaceandhas its center is'exteriorly coated with reflective material, forexampie aluminum or silver, to the extent desired. :In thisembodimentthe ellipsoidal dome 64 and 'hemispheroidal dome es along withtheir common plane connecting meansz dd are blown into such shape. inany conventional lightbulb glass blowing .manner, afterwhich the. bulbbase 7th is inserted through an aperture in the hemispherical dome sothat the filament and closer focal pointof the ellipsoidalvertex dome 64and center of the hemisphericaljdome as all coincide at point 72. .Then,all

of theexterior glass surfaces of the lamp-arercoated with stantialdistance in front of the vertex of the hemispheri This type of lightbulbmay be employed, as a general lightinglainp without using anymodifying lens to con:

.trol the output cone of light. apparent some of the light rays from thefilament at focal point 72 exit through the light aperture 74- directly,while From FIGURE 5 it is others: pass therethrough after beingreflected by one or both of the reflecting surfaces of domes 6d and 66.

.A still further. embodiment of the invention, which is especiallysuitable. as a miniaturized low candle power or wattagelong-lifereflector type lamp for bed reading purposes for examplais shown inFIGURE 6. In this em-. bodiment the ellipsoidal reflector Ydandhemispheroidal reflector 80 have the same diameter along theircoincident respective focal and equator planes, and are blown I glass asin the FIGURES embodiment. Again, the bulb base 82 extends through aside of'the hemispherical Te-' flector at an angle to the major axis ofthe ellipsoidalver- I cal surface, for example approximately the samedistance V in] front thereof. as focal point '76 is inwardly. thereof.

said focal plane.

' ofcuwature at said first focal point; said second ,doine meansincluding a-predetermined light aperturethrough. said hemisphericalsurface at its vertex centered on saidaxis, a light sourcecenteredbnsaid first focal point,

andmeans extending through'said second dome. means .at an acuteanglerelativeto said axis/ for supporting said lightsource and supplyingelectrical signals: thereto to cause substantially all the light raysemanating from said'source to pass through said light. aperture eitherdirectly or by refiection'from said reflecting surfaces, the

so reflected rays being caused by said surfaces to converge at saidsecond focal point.

2. A lamp as in claim 1 and centered on said axisat a point further fromsaid first focus than thesaid second focus so as to intercept all the Ysaid direct light rays passing through said light aperture and allot thesaid reflected light rays asthey diverge from said second focal, pointand effect a controlled cone of light.

' 3.A lamp as inclaim 2=iand dome means areintegral'and comprise a"glass envelope suitably coated to formsaid reflecting surfaces, saidlight source being. a filament. I a g J i 5 A lamp as in claim 4wherein'thesaid second dome meansis of substantially larger diameterthanthe first dome means at said focal plane. 7 6. A lamp as. in claim4- wherein said :first and second dome means are ofgsubstantially thesame diameter at 7. Alight bulb comprising trumpet turn 4 and having abase'including the said nieanswhich extends through: the second domemeans. 7 I

8. Alamp as in claim 1 wherein the last-said means and said light sourcein combination comprise a light 1 bulb, and thesaid first and seconddomemeans are external to said bulb.

9. A lamp as in claim 8 wherein the said first and. second domesreleasably connect together for changing of the. said light bulb.

further including a lens v furtherincluding a filter lens disposedbetween said second focal point and the first mentionedlens forbreakingup, light'striations.

4. A lamp as in claim 1 Whereinsaid'first and second 5 g a 10. A lamp asin claim 8 and further including a lens References Cited by the Examinerholder connected to the said second dome at said light UNITED STATESPATENTS aperture, and a plano-convex lens disposed in said holder tointercept all the said direct light rays passing through gigg 51 saidaperture and all of the said reflected light rays as 5 2338901 1/44 Chmthey diverge from said second focal point and effect a 2:876:338 3/59 gg4 2,957,073 10/60 Legge 240-735 11. A lamp as In clalm 10 and furtherincluding a 2 9 3 571 12 0 Roggan 24 4 59 filter lens disposed in saidholder on the plane side of 2 993 9 7 7 1 im said plane-convex lensbetween same and said second focal point for breaking up lightstriations. NORTON ANSHER, Primary Examiner.

1. A LAMP COMPRISING FIRST DOME MEANS FORMING AN ELLIPSOIDALINTERIORLY-REFLECTING VERTEX SURFACE HAVING A MAJOR AXIS CONTAININGFIRST AND SECOND FOCAL POINTS RESPECTIVELY AT FURTHER DISTANCES FROM THESURFACES, THE EDGE OF SAID SURFACE TERMINATING SUBSTANTIALLY IN THEFIRST FOCAL POINT PLANE WHICH IS PERPENDICULAR TO SAID AXIS, SECOND DOMEMEANS CONNECTED TO SAID FIRST DOME MEANS AND FORMING A HEMISPHERICALINTERIORLY-REFLECTING SURFACE WHICH FACES SAID ELLIPSOIDAL SURFACE ANDHAS ITS CENTER OF CURVATURE AT SAID FIRST FOCAL POINT, SAID SECOND DOMEMEANS INCLUDING A PERDETERMINED LIGHT APERTURE THROUGH SAIDHEMISPHERICAL SURFACE AT ITS VERTEX CENTERED ON SAID AXIS, A LIGHTSOURCE CENTERED ON SAID FIRST FOCAL POINT, AND MEANS EXTENDING THROUGHSAID SECOND DOME MEANS AT AN ACUTE ANGLE RELATIVE TO SAID AXIS FORSUPPORTING SAID LIGHT SOURCE AND SUPPLYING ELECTRICAL SIGNALS THERETO TOCAUSE SUBSTANTIALLY ALL THE LIGHT RAYS EMANATING FROM SAID SOURCE TOPASS THROUGH SAID LIGHT APERTURE EITHER DIRECTLY OR BY REFLECTION FROMSAID REFLECTING SURFACES, THE SO REFLECTED RAYS BEING CAUSED BY SAIDSURFACES TO CONVERGE AT SAID SECOND FOCAL POINT.